Reclining chair mechanisms have become increasingly popular over the last several decades in the residential marketplace because of their comfort and their ability to relieve minor orthopedic maladies. These reclining mechanisms fall into two or three general categories. In one conventional design the seat and chair back have no relative movement and tilt as a unit to effect the recline position. In others, the seat and back tilt but the back has a significantly greater angular movement than the seat so that significant back recline is possible without projecting the forward end of the seat upwardly to a point where the user's knees block vision of the surrounding area.
Both of these general designs have been provided in the past with extendable ottomans or leg rests. Usually, a lazy tong or scissors-type linkage is provided for supporting, extending and retracting this leg support, and this linkage is actuated in many cases by a control link pivotally mounted to the frame that has relative horizontal movement with respect to a seat frame with part of the ottoman linkage connected to the seat frame and another part connected to this control link that with appropriate geometry can extend and retract the ottoman.
In all of these reclining chair mechanisms, at least the ones that we are familiar with, the linkage mechanisms for operating the articulating functions of the chair back and the seat frame and the ottoman are located underneath the seat frame. In this location it is quite difficult to conceal the operating mechanism because some degree of flexibility must be provided. In some cases the arm assemblies are extended to cover the area under the seat which, of course, presents an obvious cosmetic problem. However, arm articulation is also common in these reclining chair mechanisms and if the arm moves up and down, it exposes the area under the seat presenting a further problem of concealment.
It should be understood that the concealment problem is not only one of aesthetics but one of safety. Exposed linkages under the chair are readily accessible to the operator's hands and also to children that may be crawling around the area of the chair. These linkage systems operate through lever principles so that very high forces can be generated by these linkage systems easily capable of breaking fingers and also larger human bones.
Elevator chair mechanisms that assist user entry and exit from a seat portion of the chair, while initially successful in the nursing home and clinic marketplaces, have only recently achieved some degree of success in the residential marketplace. Formerly believed desirable only for patients with severe lower extremity immobility, today such chair elevator or lift systems have found acceptance by users with significantly lesser handicaps including those with simply inflammatory arthritis in the lower extremity joints and other orthopedic maladies commonly found in people over 50 years of age.
In the residential marketplace, of course, the chair mechanism must be aesthetically acceptable and complementary to the home environment which necessitates the motor drive assembly be compact and located where it may be easily covered by upholstery. It also requires the lift linkages or arms be similarly located to be easily concealed by fabric. More importantly, the linkage or actuator assembly for the chair should have a low power requirement in order to reduce the size of the drive motor necessary, and decreased power consumption to provide a lift chair at a lower cost than formerly available.
There have been a plurality of attempts at designing such chair mechanisms and one is shown in the Gaffney, U.S. Pat. No. 3,250,569 which shows a conventional homestyle lounge chair where the seat moves upwardly and tilts forwardly to facilitate user exit. The design is compact and has a few number of links and for that reason it is for the most part acceptable in the residential market. However, in this chair only the seat elevates and the back remains in a stationary position with the arms, so the user has some apprehension in entering and exiting the chair because in the entry and exit position the user cannot contact the back at all and the arms are in a very depressed position relative to the seat.
There are, however, seat mechanisms designed in the past where the arms and back move upwardly and forwardly and one is illustrated in the Gaffney, U.S. Pat. No. 4,083,599. In this design the seat, back and arms are one unitary assembly all stationary with respect to one another and the chair is raised and lowered by a pair of generally parallel arms generally horizontally disposed, fixed at the rear to a stationary frame plate and at the front to a lift frame for the chair. The actuator is a screw drive and also acts as a third extending link connected at the rear to the same frame and at its front end to the forward center portion of the chair frame. This parallelogram type linkage has high power requirements and thus necessitates an excessively large motor for the residential marketplace. Also, the location of the various links underneath the chair frame require a substantial amount of additional upholstery to cover the linkage mechanism and provide a safe actuation system.
The Gorden, U.S. Pat. No. 2,608,239 shows a threaded screw actuator that raises and lowers a chair back bar with side members slidable in generally vertical grooves in vertical rails. The Gorden chair lifts as a unit and has no seat tilting.
The Ragsdale, et al., U.S. Pat. No. 2,895,539 shows a reclining exercise chair where a control link for the reclining back has a follower at its lower end that rides on a curved track that controls the pivotal movement of the back.
The Yates, et al., U.S. Pat. No. 3,343,871 shows an automatically operated invalid chair that has a reclining back and a seat frame that moves with a slotted follower mechanism to lift and seat tilt positions. There is no upward movement of the front portion of the seat upon lift.
The Re, U.S. Pat. No. 3,359,034 shows a reclining chair with a multiple scissor-type ottoman extension supported between a seat frame and a control link that pivotally carries the seat frame by spaced short lengths, but the control link moves back and forth relative to the seat frame to effect ottoman extension and retraction and at the same time seat back tilting.
Another Re patent, U.S. Pat. No. 3,758,151 shows a recliner mechanism somewhat similar to the above Re patent except that the back does not appear to articulate separately from the seat.
The Crum, et al., U.S. Pat. No. 3,858,932 shows a mechanism somewhat similar to Re's where the arms are moveable relative to the seat and a control link is utilized to operate the ottoman. But as with Re's U.S. Pat. No. 3,758,151, there does not appear to be back articulation relative to seat.
The Gaffney, U.S. Pat. No. 4,007,960 discloses a mechanism for back to seat articulation, ottoman extension and chair lift. As in the above Gaffney patent, the actuator assembly and linkage is disposed entirely underneath the seat demanding very high power requirements and this chair has problems with exposed linkages and upholstery around the linkage mechanism under the seat. Furthermore, as in the above Gaffney elevator chair, the seat back tilts forwardly upon lift which is not really desirable.
The Randolph, U.S. Pat. No. 4,077,483 shows a track-type invalid vehicle where the seat is moveable to a raised position with a generally vertical threaded screw. The screw lifts the entire chair, and there is no seat to back articulation or seat tilting.
The Andreasson, U.S. Pat. No. 4,249,774 shows a chair lift mechanism, but in this device while the seat articulates, it does so in two pieces and there is no articulation between the seat portion and the back portion.
The Booth, U.S. Pat. No. 4,545,616 shows a lift mechanism for a mobile chair with elevating seat where the seat is raised by a vertical screw that lifts the seat back. It does show articulation between the chair back and the seat frame with a generally parallelogram type linkage. Because of this four bar linkage, the back of the chair moves relatively toward the front of the seat as the chair is lifted. This is permitted by wheels that support a front link of the chair in one embodiment and the seat back in another embodiment, both designed for horizontal translating movement.
The Yoshikawa, et al., U.S. Pat. No. 4,572,573 shows a curved guide that supports the back for reclining movement guided by stationary rollers.
The Crum, U.S. Pat. No. 4,662,673 shows an away-from-the-wall recliner chair with no lift where the back articulates relative to the seat and the arms also move relative to the seat all with a rather complicated linkage system.
The Krauska, U.S. Pat. No. 4,852,939 shows a device for converting or retrofitting a recliner chair to a recliner lift chair with a mechanism somewhat similar to the mechanism shown in the Gaffney, U.S. Pat. No. 4,007,960 described above, except that it does appear that Krauska's arms articulate relative to the seat. Krauska does not include any chair back to seat articulation and note that the seat frame is pivotally mounted by spaced short links on a control rail that scissors with the seat frame to effect ottoman scissor linkage movement.
It is a primary object of the present invention to provide an improved reclining mechanism both with and without elevation that ameliorates the problems noted above in prior art reclining systems.